Oscillation Decoupling Device

ABSTRACT

What is described is an oscillation decoupling device with a load-receiving element which is mounted in an oscillating manner relative to a support unit at least along an active direction along which at least part of the load is applied, and with at least one sensor-actuator unit which detects an oscillation of the element due to the load and acts against the oscillation of the element by means of actuators. 
     The invention is characterised in that the support unit is modularly configured and serves as a support structure for at least one unit that receives the element and is elastically deformable in the active direction of the load, in that the load-receiving element is connected to the elastically deformable unit, and in that an actuator influencing the deformation is applied to the at least one unit, or is integrated in it, so that the actuator initiates a deformation acting against an elastic deformation due to the load inside the unit.

TECHNICAL FIELD

The invention relates to an oscillation decoupling device with a load-receiving element which is mounted in an oscillating manner relative to a support unit at least along an active direction along which the at least one part of the load is applied, and with at least one sensor-actuator unit which detects an oscillation of the element due to the load and acts against the oscillation of the element by means of actuators.

STATE OF THE ART

In almost all fields of the art oscillation problems arise which must be solved, for example by decoupling a partial structure from its vibrating environment. Typical examples of this are mountings of measurement sensitive measuring apparatus in laboratories for decoupling impact noise and other disturbances by means of suitably designed damping systems, but similar problems also arise in aviation and space systems. On the other hand it is necessary to decouple sources of disturbing vibrations from a structure surrounding them, as frequently encountered, for example, in the mountings of drive units in vehicles, aircraft or ships.

For this purpose differently designed oscillation decoupling devices are known which exert a purely passive oscillating action with the use of elastic or damping materials. However, the disadvantage of these devices lie in the fact that it is not possible to adapt to changing system characteristics in order to maintain as optimum an oscillation damping as possible. Moreover, although the use of the softest possible mountings results in effective oscillation damping or oscillation decoupling, this is also associated with imprecise mounting of the decoupled system. On the other hand, although stiffer mounting systems allow more precise system positioning, the quality of the oscillation decoupling suffers correspondingly, particularly in the case of oscillations with small amplitudes and high frequencies.

In addition to purely passively designed oscillation decoupling systems, mechatronic and adaptronic solutions are being used to an increasing extent, the oscillation decoupling here being achieved by means of actively introduced compensation signals which serve for the controlled activation of electrodynamic actuators, magnetic bearings or piezo-actuators which are integrated in the region of oscillation decoupled interfaces and make an active contribution to oscillation decoupling, in the sense of an oscillation reduction, for the specific coupling of counter-oscillations.

Reference is made, by way of example, to U.S. Pat. No. 5,645,260, which describes an oscillation decoupling device which is provided between a load and a vibrating background. The load rests essentially on an elastic support structure in the form of a jib angle along whose jib elements, orientated perpendicularly to each other, are installed flat piezo-actuators which are capable of inducing both horizontally and vertically directed oscillations into the jib angle due to their arrangement orientated orthogonally to each other, with the ultimate object of effective oscillation decoupling. The prior art arrangement of the piezo-actuators also has the advantage that the actuators are largely protected from damaging mechanical loads by the support structure.

A further modular interface for damping mechanical oscillations is disclosed in DE 103 61 481 A1, which provides for a plurality of energy converter systems kinematically coupled to each other between a basic connecting element and a load connecting element, which systems, in a similar manner to the oscillation decoupling system explained above, are based on the specific control of piezoelectric converter materials. However, the energy converter systems, designed as piezoelectric stacking actuators, are operated under mechanical pretension and are protected against loading by shearing and torsion, hence the need for comprehensive mechanical protective measures for the actuators.

The oscillation decoupling devices of prior art predominantly represent systems that are individually adapted to certain interfaces between two components to be oscillation decoupled. These systems cannot be used in other systems to be decoupled or can only be used in them with expensive design modifications. Moreover, the integration of the piezo-actuators in the structure concerned represents a high construction expenditure which is unavoidably associated with high production and assembly costs.

Representation of the Invention

The object of the invention is to further develop an oscillation decoupling device with a load-receiving element which is mounted in an oscillating manner relative to a support unit at least along an active direction along which at least part of the load is applied, and with at least one sensor-actuator unit which detects an element that is oscillating due to the load and acts against the oscillation of the element by means of actuators, so that the device can be used universally and represents no special solution to an individual oscillation problem. The device should on the one hand have the advantages of an elastically passive mounting with actuating components, and should at the same time provide the possibility of integrating all the components in one structural unit for independent operation. This should provide a system that is easy to handle, is robust and can be used under difficult environmental conditions.

The object of the invention is achieved as indicated in claim 1. Features advantageously further developing the inventive concept constitute the subject matter of the dependent claims and may be deduced from the description, with particular reference to the exemplary embodiments.

According to the inventive solution an oscillation decoupling device is represented with a load-receiving element which is mounted in an oscillating manner relative to a support unit at least along an active direction along which at least part of the load is applied, and with at least one sensor-actuator unit which detects an element oscillating due to the load and acts against the oscillation of the element by means of actuators, characterised in that the support unit is modularly configured and serves as a support structure for at least one unit that receives the element and is elastically deformable at least in the active direction of the load. At least one actuator influencing the deformation is applied to the at least one unit, or is integrated in the unit, so that the actuator initiates a deformation acting against the elastic deformation due to the load inside the unit.

The inventive device is based on the modular concept and the associated simple, versatile applicability of the inventive device. The support unit serving as the support structure for the elastic unit is designed as a fixed module housing which accommodates the elastically deformable unit provided for oscillation absorption and the actuators attached to or provide on it for the specific introduction of counter-oscillations, the unit and actuators being protected from disturbing external oscillation influences. The stiffness of the elastically deformable unit must be chosen according to the size and intensity of a static and/or dynamic external load to be decoupled, which unit, in a preferred embodiment, is designed in the manner of a membrane and spans an internal free cross-sectional area of the module housing so that is freely supporting, and is connected on the inside, in at least two regions, preferably throughout its circumferential edge, to the module housing. The elasticity and stiffness or stroke of the flat designed, elastically deformable unit can therefore be correspondingly adapted based on the choice of material, shape and thickness. The elastically deformable unit therefore represents the elastic, passive part of the oscillation decoupling system, and is connected indirectly or directly to an element which is preferably designed in the manner of a rod and is orientated perpendicularly to the superficial extension of the elastically deformable unit along which the external load to be decoupled acts, which ultimately results in a deflection or deformation of the elastically deformable element perpendicularly to the superficial extension of the element.

A further possibility of adjusting the stiffness behaviour of the elastic, passive part of the oscillation decoupling system consists in providing two or more elastically deformable units inside a module housing which can be mechanically connected in parallel or in series. In the former case a coupling of the at least two elastically deformable units to an element designed in the manner of a rod must be provided, whilst in the latter case this coupling is not provided, and the elastically deformable units are therefore able to absorb a proportion of the external static and/or dynamic loads.

A mechanically serial and/or parallel connection of two or more modules is also possible. In this case the parallel connection of modules serves to increase the oscillation stroke. In this case the elements of the modules designed in the manner of rods are not connected to each other, whilst the serial connection serves to increase stiffness and hence to transmit higher forces. In a preferred embodiment the elements of the modules designed in the manner of rods are connected to each other.

Moreover, combinations of modules connected mechanically in parallel and in series are conceivable. For a clearer representation of the inventive concept it is assumed in the following that only one single elastically deformable unit designed in the manner of a membrane is provided inside the previously described module housing.

For an effective reduction of the oscillations induced by an externally applied dynamic load inside the elastically deformable unit designed in the manner of a membrane, the latter is connected to at least one, preferably a plurality of flat designed electromechanical converters or actuators which, when suitably controlled, give rise to controlled deformation of the elastically deformed unit designed in the form of a membrane. Piezoelectric plate actuators, which are applied to and/or integrated in the surface of the elastically deformable unit designed in the manner of a membrane, and which expand or contract due to the application of an electric voltage, as a result of which they introducing a bending moment into the elastically deformable unit and produce a bend perpendicular to the superficial extension of the unit, are particularly suitable as electromechanical converters. This enables actuators to intervene in the oscillation behaviour of the elastically deformable unit in a specifically controlled and regulated manner in or against the active direction of the external load.

In a preferred embodiment at least one sensor detecting the deformation of the unit is applied to the elastically deformable unit, or is integrated in the unit, for detecting the current oscillation state of the elastically deformable unit. In a similar manner to the actuator principle explained above, an electromechanical converter, for example in the form of a piezoelectric plate sensor, which generates a voltage signal that can be evaluated by measurement by way of a deformation, is also suitable for the sensor, which signal is used for controlling or regulating the actuators connected to the elastically deformable unit. Alternatively to or in combination with sensorics connected directly to the elastically deformable unit, it is also possible to install corresponding sensors, for example in the form of acceleration sensors, in the region of the load or the body to be decoupled, for example directly on the oscillating body connected to the element or in the load path of the load along the element which is connected to the elastically deformable unit designed in the manner of a membrane. Independently of the different designs and installation of the sensors, it is necessary to detect the oscillation behaviour of the at least one elastically deformable unit integrated inside the module housing. in order to generate control or regulating signals for activating the at least one actuator connected to the elastically deformable unit, with the object of reducing the externally applied oscillations along the elastically deformable unit designed in the manner of a membrane.

The processing of the signals generated by the sensors, and the generation of corresponding control signals for the actuators, are preferably carried out with suitable control logic which is preferably based on digital signal processing and, for reasons of cost, can be implemented on so-called low-cost embedded platforms such as DSP, microcontrollers and FPGA.

In principle it is possible to install any electrical components required both for energy supply and signal evaluation together with the components explained above inside the module housing. In order to obtain and optimise the modularity of the inventive device it would appear advantageous to provide a modularly configured electronic unit that can be integrated in the module housing or can be applied to the existing module housing for energy supply and/or signal control and/or signal evaluation of the at least one sensor and actuator. It is appropriate to design the electronic unit required for the energy supply and signal control of the individual actuator modules combined together in the form of a separate electronic module, particularly for the purpose of combining two or more module housings, each of which has at least one elastically deformable unit with corresponding sensorics and actorics and are connected by means of a common element for receiving an external static and/or dynamic load are designated as actuator modules in the following. The electronic module has its own module housing and can be combined to form an entire system by means of a suitable mechanical, as well as electrical connection system via at least one of the combined actuator modules.

Of particular interest is the design of the inventive oscillation decoupling device in the form of a completely autonomously and largely independently operating unit, i.e. all the components required for effective oscillation decoupling, including the energy supply, are joined together in the form of individual modules to form one entire system which can be inserted as an interface between an oscillating body and a corresponding base surface.

In the case of an adaptively configured actuator control for specific deflection of the membrane-like configured elastically deformable unit inside an actuator module, it is possible to supply the reference signals required for controlling the actuators connected to the elastically deformable unit from outside, for example wirelessly using an intrinsically known telemetry technique. It is therefore possible, for example, correspondingly to suppress disturbing vibrations of a rotary machine by externally gained speed-synchronous trigger signals, which are supplied telemetrically as reference signals to the actuators inside the actuator modules. In this case no further sensors are required for detecting the current oscillating state of the elastically deformable unit, particularly as the actuators are controlled by externally predetermined trigger signals which are frequently available via existing bus systems. If such external trigger signals are not available, there is also the possibility of estimating the interference signal by means of one or a plurality of acceleration sensors applied to the interference source, as a result of which suitable reference signals can also be generated.

The use of digital signal processing for control implementation, particularly when a plurality of devices configured modularly according to the invention is used, which are provided, for example, on a vibrating machine for support at different points for oscillation decoupling, provides the interesting possibility of exchanging data with an externally provided central computer. For this purpose each individual oscillation decoupling module, each of which consists of one actuator and one electronic module, provides a telemetry unit for wireless data transmission. Obviously it is also possible, but in most cases associated with technical and design difficulties, to data to be exchanged with a central computer on a wire-bound basis. The reference signals controlling the individual oscillation modules can be optimised by the central collection and evaluation of all the information on an oscillating system. It is also possible to carry out self-diagnoses in each individual oscillation decoupling module on the basis of digital signal processing, which diagnoses serve to optimise control parameters for controlling the individual actuator modules by feedback to the central computer.

BRIEF DESCRIPTION OF THE INVENTION

The invention is described by way of example below, without limiting the general inventive concept, by means of exemplary embodiments with reference to the drawings, in which:

FIGS. 1 a, b show a schematised longitudinal section and partial longitudinal section, respectively, through an actuator module,

FIG. 2 shows a schematised longitudinal section representation through a modularly configured oscillation decoupling device,

FIG. 3 shows a schematised perspective representation of the module sown in FIG. 2,

FIG. 4 shows a module arrangement for the oscillation decoupling of an oscillating unit,

FIGS. 5 a-c show a schematised cross-sectional representation through an actuator module with an elastically deformable unit,

FIG. 6 shows the mechanical series connection of two actuator modules, and

FIG. 7 shows the mechanical parallel connection of two actuator modules.

METHODS OF IMPLEMENTING THE INVENTION, COMMERCIAL APPLICABILITY

FIG. 1 a shows a schematised longitudinal section representation through an actuator module which is enclosed by a module housing 1 designed essentially in the shape of a hollow cylinder. Module housing 1 serves as a supporting structure for an electrically deformable unit 2 designed in the manner of a membrane and installed inside module housing 1, which unit, as a flat element similar to a leaf spring, at least partially spans the internal free housing cross-section and is fixedly connected to its peripheral circumferential edge to the inner wall of module housing 1. An element 3, designed in the shape of a rod, is installed centrally to the flat or membrane-like configured elastically deformable unit 2, the longitudinal rod extension of which element is orientated essentially perpendicularly to the plane of the flat design of unit 2, and along which an external load L is applied to actuator module A, and in particular to the elastically deformable unit provided in actuator module A.

Element 3 may be connected fixedly or releasably to elastically deformable unit 2, for example by way of a screw connection. Elastically deformable unit 2 is deformed perpendicularly to its superficial extension by the predesigned introduction of a force from an external static or dynamic load L via element 3. In order to counteract these externally induced deformations to which elastically deformable unit 2 is exposed, in an oscillating damping manner, flat designed, energy converting actuators 4 are installed on the surfaces of the membrane-like configured elastically deformable unit 2, these actuators preferably produced from piezoceramic, lead-free piezoceramic, an electrostrictive ceramic, PVDF (polyvinylidene fluoride), magnetostrictive alloys, bi-metals or from a shape memory alloy or shape memory polymer, all converter materials which are capable of changing their spatial shape in terms of their length by means of an external electrical voltage supply.

FIG. 1 b shows a schematised partial longitudinal section through an actuator module A sown in FIG. 1 a, with two flat designed piezo-actuators 41, 42 installed on the upper and lower side of elastically deformable unit 2, which actuators are controlled in such a manner that piezo-actuator 42 installed on the upper side of membrane-like configured elastically deformable unit 2 is shortened, whereas piezo-actuator 41 provided on the lower side is expanded. As a result of this elastically deformable unit 2 experiences an upward directed curvature in the representation according to FIG. 1 b, causing element 3 to be deflected upwards.

The principle of the oscillation decoupling provides for the actuator effected deflection of elastically deformable unit 2, e.g. in exactly the opposite phase to the load L applied externally via element 3.

Furthermore a plurality of sensors 5 is installed on and/or integrated in the upper and lower side of the membrane-like configured elastically deformable unit 2, which sensors may also exist as the actuators produced from a converter material. Obviously it is possible to design the sensors as DMS's or the like, in order to detect the current deformation state and associated with the current oscillation state of elastically deformable unit 2, and to generate corresponding sensor signals.

FIG. 2 shows a schematised longitudinal section representation of an oscillation decoupling module SM, consisting of two actuator modules A1 and A2 connected mechanically in parallel and an electronic module E connected to actuator module A2. Actuator modules A1 and A2 are correspondingly designed according to the above statements relating to FIGS. 1 a and b, and each have an elastically deformable unit 2, all of them connected to a single element 3 by means of which the external load is applied to oscillation decoupling module SM. For the energy supply, but in particular also for data evaluation and controlled signal supply to actuators 2, an electronic module E is provided which, for reasons of compact design, is formed in the same or a similar manner in terms of housing design as actuator modules A1 and A2. All modules A1, A2 and E have mechanical interfaces which facilitate the coupling together of the module units. The electronic module comprises a power conditioning unit 6, which supplies the energy for controlling the actuators, for example in the case of piezo-actuators in the form of a voltage amplifier and components of signal data evaluation unit 7 and 8, in which sensor data are supplied and evaluated in order finally to generate control signals for activating the actuators.

Provision is preferably made for the electrical contacting between the electronic components contained inside actuator modules A1 and A2 and those in electronic module E by means of suitably designed connection contact points (not shown), in order to conform to the modularity principle. Depending on the loads applied, oscillation decoupling module SM provides the possibility of increasing the stiffness of the passively elastic parts, i.e. the elastically deformable units, by adding further actuator modules.

FIG. 3 shows, in schematised form, an oscillation decoupling module SM composed of two actuator modules A1 and A2 and an electronic module E, from whose upper housing end projects element 3, by means of which external load L is introduced and supported for the purposes of oscillation decoupling. Oscillation decoupling module SM is fastened to a stable base 9 so that precise positioning is ensured. On the other hand the module could also be installed on an elastic structure, but this depends on the particular application.

The exemplary embodiment shown in FIG. 4 provides for the oscillation decoupling of an oscillating unit 10, which is mounted at four support points P1, P2, P3 and P4 on suitably designed oscillation decoupling modules SM. In this design variant the individual oscillation decoupling modules SM have telemetry units by means of which the reference signals sent from central computer 11 for controlling the actuators contained in oscillation decoupling modules SM are transmitted and received. Similarly all sensorically detected data can be evaluated centrally by means of such wireless data communications technology on the oscillating state of unit 10 to guarantee optimised control of the corresponding actuator modules inside oscillation decoupling modules SM.

A section through an actuator module in the plane of the membrane-like configured elastically deformed unit 2 is shown in the cross-section diagrams in FIGS. 5 a to c. In all cases module housing 1 is designed in the shape of a hollow cylinder and has a membrane-like configured elastically deformable unit 2 connected to module housing 1 along its entire circumferential edge. In FIG. 5 a an annular designed actuator element 4 is provided on the surface of elastically deformable unit 2, which element represents an internal superficial connection to unit 2. In the exemplary embodiment shown in FIG. 5 b the membrane-like configured elastically deformable unit 2 has four recesses 12, and is also connected on its surface to four strip-shape configured actuators 4. FIG. 5 c also shows provides for an actuator in the form represented, connected in the form of a strip to elastically deformable unit 2. All the exemplary embodiments shown in FIG. 5 serve specifically to deform the membrane-like configured elastically deformable unit perpendicularly to its plane, i.e. perpendicularly to the drawing plane, in order to achieve an effect that reduces the oscillating load, for example by introducing oscillations that are opposite in phase to the external load.

FIG. 6 shows, similarly to FIG. 2, a mechanical serial connection of Module A1 and A2, where, in contrast to the exemplary embodiment shown in FIG. 2, rod-like configured element 2 is constructed separately. Force L2 can be applied by means of element 3′ to elastically deformable unit 2 of lower actuator module A2, independently of force L1, which is applied by means of element 3″ to the elastically deformable unit of upper actuator module A1. In the case of such a serial arrangement and mode of operation of at least two actuators, the actoric path can be doubled under sufficiently low active loads or low stiffnesses, whereas in the coupled case according to the embodiment shown in FIG. 2, a doubling of the stiffness is achieved. An alternative to the embodiment in FIG. 2 is shown in FIG. 7, which represents a further type of mechanical parallel connection of a plurality of actuator modules. In this case the two actuator modules A1 and A2 are connected to each other by means of a common base plate G. Similarly, elements 3 of actuator modules A1 and A2 are connected to each other by means of a yoke J, so that they are simultaneously deflected by means of a common load L.

The oscillation decoupling module explained above therefore has the following advantages:

The system can be fully integrated and affords major advantages in terms of mountability and robustness; The combination of a membrane-like configured elastically deformable unit having a defined stiffness with the application and/or integration of flat designed actuators allows particularly compact design of an active-passive oscillation decoupling system; Because of the additional application and/or integration of flat sensors on the membrane-like configured elastically deformable unit the robustness and compactness of such an oscillation decoupling module can be improved. The specific use of digital signal processing opens up the possibility of providing adaptive digital controls to ensure optimum oscillation decoupling despite variations in the interference signals or in the system characteristics. Furthermore, it is possible, on the basis of digital signal processing, to provide communication with an extern computer in order to allow the exchange of diagnosis data. This improves the possibility of maintaining such a system, particularly as the regions in which the oscillation decoupling modules are arranged are in most cases difficult to access and cannot easily be removed for servicing purposes.

LIST OF REFERENCE NUMBERS

1 Module housing 2 Elastically deformable unit

3 Element 4 Actuator 5 Sensor

6 Energy unit 7, 8 Components of a signal data evaluation unit

9 Base

10 Oscillating unit 11 Central computer 12 Recess 

1-18. (canceled)
 19. An oscillation decoupling device with a load-receiving element connected to a unit that is elastically deformable in the active direction of the load, which unit is mounted in an oscillating manner relative to a support unit at least along an active direction along which at least part of the load is applied, and at least one sensor/actuator that detects the oscillation of the element due to the load and acts against an oscillation of the element by means of actuators, wherein at least one actuator influencing the deformation is applied to the at least one elastically deformable unit, or is integrated in the unit in such a manner that the actuator initiates a deformation acting against the elastic deformation due to the load inside the unit, characterised in that the support unit is designed as a modular housing which fully encloses the elastically deformable unit, in that the modular housing together with the at least one elastically deformable unit and the load-receiving element are designed as an actuator module, and the module housing has a mechanical and electrical connection system by means of which a mechanical and electrical coupling to at least one further similarly designed actuator module is possible, wherein the module housings of the at least two actuator modules are actively connected to each other in a coupled state and the load-receiving elements of both actuator modules are connected to each other, or a single element is provided which connects the at least one elastically deformable unit of each actuator module mechanically to each other, in that a modularly configured electronic unit is provided for the energy supply and/or signal control and/or evaluation of the at least one sensor and actuator, which unit is enclosed by an electronic module housing which has at least one connecting structure by means of which the electronic module housing can be mechanically coupled to an actuator module, and in that at least one electrical connecting system is provided by means of which the at least one sensor and/or actuator can be contacted with the modularly configured electronic unit.
 20. The device according to claim 19, characterised in that at least one sensor detecting the deformation of the unit is applied to the at least one elastically deformable unit or is integrated in the unit.
 21. The device according to claim 19, characterised in that a sensor detecting the deformation of the unit and/or a force and/or an acceleration sensor is provided in the region of the load and/or in the load path of the load along the element.
 22. The device according to claim 19, characterised in that the element connected to the elastically deformable unit projects at least on one side from the housing.
 23. The device according to claim 19, characterised in that the elastically deformable unit is designed in the manner of a membrane, spans a free cross-sectional area of the support unit in a freely supporting manner, and is connected to the support unit preferably around the entire circumferential edge of the elastically deformable unit.
 24. The device according to claim 19, characterised in that the element is designed longitudinally in the manner of a rod has a longitudinal extension directed orthogonally over an elastically deformable unit designed in the manner of a membrane.
 25. The device according to claim 24, characterised in that the element is arranged centrally in relation to the elastically deformable unit and is connected to it.
 26. The device according to claim 23, characterised in that the at least one actuator is applied to the surface of the elastically deformable unit designed in the manner of a membrane or is integrated in it.
 27. The device according to claim 19, characterised in that the at least one sensor and/or actuator has a converter material or consist of a converter material selected from one of the following material classes: piezoceramic, lead-free piezoceramic, electrostrictive ceramic, shape memory alloy, shape memory polymer, PVDF (polyvinylidene fluoride), magnetostrictive alloy or bi-metals.
 28. The device according to claim 27, characterised in that the actuator experiences a longitudinal extension or a shortening due to controlled energy supply, which extension or shortening is influenced by the contact with the elastically deformable unit in the form of a deformation of the elastically deformable unit directed against the active direction of the load.
 29. The device according to claim 27, characterised in that mechanical energy is converted to electrical energy by the elastic deformation of the converter materials, at least one part of which energy may be used to operate at least parts of the electronic unit.
 30. The device according to claim 19, characterised in that power electronics are provided inside the electronic unit so that the actuator module can be operated largely independently.
 31. The device according to claim 19, characterised in that the electronic unit is constructed on the basis of digital or analogue signal processing.
 32. The device according to claim 19, characterised in that the electronic unit has a telemetry unit by means of which a wireless data exchange to control and evaluation unit provided separately from the device is possible. 